Method of compressing and compacting a solid body of metal



May 17, 1960 J. DE STERNBERG 2,936,520

METHOD FOR COMPRESSING AND COMPACTING A soup BODY OF METAL Filed April 19, 1957 2 Sheets-Sheet 2 United States Patent METHOD OF COMPRESSING AND COMPACTING A SOLID BODY OF METAL The invention relates to a process for compressing and more particularly making metals, iron and steel alloys,

compact, for example, in the shape of blocks intended subsequently to be treated by rolling, drawing or the like.

The object of the invention is to enable a compression under very high pressure to be obtained and consequently a volumetric reduction never yet reached of blocks intended to be used for industrial work. Alloys of metals and steel already have 30,000 kg./cm. for their compression, a considerable change in their molecular state and their characteristics being well above that obtained by forging or rolling.

The purpose of the invention is a process for compressing and making more compact a metal or an iron or steel alloy, for example, in the shape of a block intended subsequently to be treated by rolling, drawing or the like, said process characterized in that the body to be compressed, enclosed in the cold state in a receiver is subjected to a first compression beyond the extrusion limit, preferably by means of a hydraulic pressure not producing gas, up to a preferable pressure of about 30,- 000 kg./cm. the body is subjected to a final pressure (preferably to an extent exceeding 300,000 kg./cm. with co-operation of the hydraulic pressure means com pressed in the first stage beyond the elastic limit, by causing forces to act on this means set up by the dilatation of a material, preferably liquid, with a high dilatation coefficient such as mercury contained in a column.

In one form of application of the process, the pressure means utilized for compressing the body is formed of graphite and molybdenum sulphide in a plastic state subjected to the action of a piston or a pump.

Thus, a rapid heating of the dilatable material occurs up to a temperature rising preferably to about 200 centigrade. In this manner, it is possible for the first time to attain extremely high pressures. By employing a hydraulic pressure means of a known type, in a press piston or pump, for the preliminary compression and passing the elastic limit, a process of rational pressing can be achieved that is free from difficulties.

Lastly, the invention relates to a part or block of metal or alloy according to that obtained by the application of the above-mentioned process or a similar process.

The invention also applies to the characteristics arising out of the following description and the attached drawings, as well as to their possible combinations.

The description applies to examples of embodiment of the invention shown in the drawings, in which:

Figure 1 shows the press without its piston in a m: gitudinal section with the block deposited in the receiver for compressing;

Figure 2 is a section along II-lI of Figure 1, with the cylinder, the advance piston and the closing slide.

Figure 3 is a cross-section along III-III of Figure 1, through the annular body with the bores for the high pressure columns as well as the insulators with the core and cover.

The receiver 1 receives the block to be compressed 2.

After positioning the block the self-tightening closing member 3 is slipped into the open end of the receiver 1 and the whole is locked by a hydraulic locking device or a mechanical device (not shown). In the axis of the receiver, provision is made, in the example of Figure l, for a closing slide 4 movable in the body and which is connected by a rod 5 to a piston shown in Figure 2. After having slipped on the closing device 3 the slide 4 is drawn backwards by means of the rod 5 so that the piping 6 is freed. The receiver 1 is then filled with the hydraulic pressure means in the shape of a plastic mass of graphite and molybdenum sulphide by means of a press piston or the like (not shown), as indicated by the arrows, through the junction duct 7. After obtaining the first pressure stage, for example, 30,000 kg./cm. in the receiver 1 for pre-compressing the block, an advance movement of the closing slide 4 is effected by means of the piston 5. As shown in Figure 2 a discharge slide 8.is brought backwards by means of a hydraulic piston (not shown). The slide 8 thus frees the entrance to a duct 9 towards an accumulating tank (not shown). The slide 4 also acts at the same time as a safety valve. If an undesirable pressure appears in the receiver 1, it may overcome the load pressure of the piston 5 so that the latter will yield and the pressure means regulated on the pressure contingently provided may discharge through the duct 10. The over-pressure existing in the receiver is then discharged through the bore and the duct 9.

At right angles to the body containing the duct 7, there is an annular body 11 having covers 12, 13, 14 and a part forming a core 15. In the annular body 11 several longitudinal drillings v16 are made, arranged on a circumference and which communicate through the drillings 17 with a central depression duct 18 which emerges in the junction duct 7. On the internal and external periphery of part of the annular body 11, insulators 19, 20 are provided which rest against rings of fretted metal 21, 22. Steel pins 23 themselves ensuring tightness are inserted in the bores 16 as far as the rings 21, 22. They abut downwards against disks of fretted metal 25 which are set in the hard steel ring 24 to prevent the pins from traversing the plates under the effect of the pressure. Above the pins 23 the bores 16 are filled with mercury. The mercury columns extend practically to the top end of the insulators 19, 20 and act on the graphite-molybdenum sulphide pressure means which fill the bores 17 and the pressure duct 18, said pressure means arriving through the junction duct 7.

Tightness is ensured by steel pins 26 with hard steel disks 27 inserted from the outside into the bores 17 nearly up to the arrival point of the drillings 16. The height to which the bores 16 are filled with mercury must in any case be such that, when the mercury dilates by heating, its passing into the duct 7 is prevented.

In order to secure a rapid heating of the mercury columns, an electric heating device 28 is provided which is switched olf once the pressure value is reached and the pressure duration has elapsed. Then, in order rapidly to cool the mercury columns to normal temperature, a cooling device of the cooling coil kind is provided in the core 15.

After the mercury columns return to their reduced dimensions, the closing slide 4 is brought backwards. The over-pressure still existing and which is set up by the elasticity of the pressure fluid in the receiver 1 and duct 7, discharges through the duct 9, towards the accumulating tank.

After opening the breech 3, the compressed block 2 can be withdrawn from the receiver.

A junction duct 30 can be provided towards an electronic manometer (not shown).

I What Iclaim is:

1. Method fortcompressing and compacting a solid body of metal, which comprises enclosing said body cold in a vessel, then subjecting said body to a first hydraulic pressureabove the limit of flow supplied by a piston press yielding about 30,000 kg/crn. and transmitted cury, contained in a column and heated to 200 C., the hydraulic pressure being transmitted to the-vessel through bores formed in an annular body which contain the expansible liquid.

2. Method for compressing and compacting a solid body of metal, which comprises enclosing said body cold 'in a vessel, then subjecting said body to a first hydraulic pressure above the limit of flow supplied by a piston press yielding about 30,000 kg./cm. and transmitted through hydraulic pressure means such as a mixture of 56,807 Shearman July 31, 1866 720,348 Holzer Feb. 10, 1903 20 1,094,092 Oyster Apr. 21, 19.14

1,710,776 Langenberg -Apr. 30, 1929 1,782,103 Solberg Nov.v 18,1930

graphite and molybdenum sulphide in plastic condition, without producing gas, and then subjecting the body through said hydraulic pressure means to a very high final compression of the order of 300,000 kg/cm. by causing action on the hydraulic pressure means of force created by linear dilation of a confined material, preferably a liquid with high coefficient of expansion such as mercury, contained in a column and heated to 200 C., the hydraulic pressure being transmitted to the vessel through bores formed in an annular body which contain the expansible liquid, and externally controlling the heating and cooling of the expansible liquid in the annular body.

References Cited in the file of this patent UNITED STATES PATENTS 

